During the time since the first dome structure was constructed, that could be called “Geodesic”; on top of the roof of the Carl Zeiss Optical Company in Jena Germany in 1922, the Science of Geodesic domes and structures has grown and evolved substantially. Shwam in U.S. Pat. No. 4,907,382 provides a categorization of various systems of Geodesic Domes and types of Fabrication. Shwam defines “Geodesic Domes” as being characterized such that “the outer surfaces of all Geodesic Domes are (either actual or implied) subdivided into triangles” In Mathematical terms “Geodesic” is defined as being “the shortest path between two points on any surface”. In Civil Engineering terms “Geodesic Structures” are defined to be “structures consisting of a large number of a few identical parts and therefore simple to erect; and whose pressure is loadshed throughout the structure, so that the larger it is the greater it's strength”. The Geodesic Dome is known to a very strong structure and the only structure that becomes stronger as it's becomes larger.
Pioneering work in the formation of geodesic domes was achieved by Robert Buckminster Fuller U.S. Pat. No. 2,682,235. A detailed description of the forces present in the geodesic domes proposed and constructed by Buckminster fuller is given by Lanahan U.S. Pat. No. 7,452,578 B2. Fishbeck in U.S. Pat. No. 7,389,612 provides a detailed description of the framework and planar elements used in the formation of the domes constructed by Buckminster Fuller.
Fishbeck also discusses the merits of constructing spherical structures from simple structural elements that are easily manufactured rather then the planar elements needed to be fastened along predetermined gridlines as in the domes constructed by Buckminster Fuller. So these merits will not be discussed again here.
A detailed description of geodesic spheres formed from pentagonal and hexagonal elements in terms of analytical spherical geometry can be found in U.S. Pat. No. 4,679,361 by Craig Yacoe. Other methods of constructing geodesic structures from discrete elements for diverse uses have been proposed; Lanahan U.S. Pat. No. 7,452,578 proposed structural fabrics formed from interconnecting uniform arrays of icosahedra members and also interconnecting carbon-60 molecule icosahedrons with these structural fabrics having a diverse range of applications. Mori U.S. Pat. No. 4,509,500 proposes a solar energy collection apparatus as part of a transparent geodesic sphere. In terms of this present invention, the geodesic sphere proposed by Mori is formed from 1st level Hexagonal and Pentagonal elements but as will be understood from this disclosure, this is not the most practical method of constructing a geodesic sphere.
Roberts U.S. Pat. No. 5,560,151 describes a method of constructing geodesic domes constructed from hexagonal and pentagonal building blocks that are formed from a lower level of tri-angular building blocks. These building blocks described in the Roberts disclosure show indentations on the inner side joining surfaces of the blocks to facilitate the cementing together of the blocks and also orifices on the outside surfaces of the blocks which can be used by fasteners to hold the blocks together. But by either methods such an assemblage of building blocks will be reduced to a pile rubble in a powerful enough earthquake. Roberts proposes a building structure comprising 90 percent weight of ceramic material. Again, in an earthquake an enclosure made mostly from ceramics will crack-up and crumble. The Roberts disclosure proposes a building structure comprising of 90 percent weight of plastic material; Should a fireball erupt inside such an enclosure the intense heat could collapse the structure. The Roberts disclosure proposes building structure is proposed comprising 90 percent weight of metal but it will be the same scenario should a fire erupt inside the building structure. Such deficiencies in methods of the prior art require methods of creating structural assemblages using building parts which not only can be fastened together in a robust manner but also combine at least two different materials with this combination protecting the structural assemblage from harsh conditions in the environment. This is especially important because there is no one material in existence possessing all the intrinsic properties to withstand the combined effects of excessive heat; excessive shock; excessive vibration; and excessive force impacting upon it.
The method of constructing geodesic structures of this present invention differs from the prior art in that the hollow hexagonal pyramidal frustums and the hollow pentagonal pyramidal frustums can be fastened together using bolts that protrude through each interior side of each joining frustum in the network of frustums which are formed from lower levels of hollow polygonal pyramidal frustums so that what is infact obtained is a mosaic of pyramidal frustums all fastened together to provide a structure of superior strength.
Fishbeck U.S. Pat. No. 7,389,612 proposes geodesic structures made from discrete elements which can be assembled to form a geodesic dome. The geodesic dome proposed by Fishbeck is made up of discrete elements referred to as ‘hub elements’ in an ‘approximate’ fashion in that the elements are overlapping or tangentially touching adjacent elements. Fishbeck proposes various kinds of hub elements, amongst these elements a tapered tri-angular tube element that can be used to construct a structure with curvature such as a geodesic dome. The embodiment of this present invention differs from the method proposed by Fishbeck in that the elements used in the formation of geodesic structures disclosed herein are, to be precise, hollow pyramidal frustums formed from lower levels of hollow pyramidal frustums and significantly different from the tapered tri-angular hub elements proposed by Fishbeck; the angle by which the sides of the hollow pyramidal frustums slant must be precisely calculated so that each side of each truncated hollow cone in the geodesic network will join in a flush join such that the entire length and width of the joining surface will be a flush join.
This requires that the elemental hollow pyramidal frustums, be specially manufactured by methods of sand-casting or die casting. It must also be stressed that this invention requires that the hollow pyramidal frustums be designed so that all the side faces joining together do infact join together for the ‘entire’ length of the side surface. Unless the structure consists of a network of flush joins it will not be inherently robust and provide an ultimate strength for a specific material of specific tensile strength. It also needs to be stressed that if one is to attempt to construct a spherical enclosure such as a geodesic dome using the tapered triangular tubes proposed by Fishbeck by the method disclosed herein then two different tri-angular tubes would be needed; hollow equilateral tri-angular tubes to form the lowest level hexagonal pyramidal frustums and hollow isosceles tri-angular tubes to form the lowest level pentagonal pyramidal frustums. But then the design problem becomes vastly complicated because to achieve totally flush joining surfaces the angles by which the side surfaces of the tubes taper will be different on the isosceles tri-angular tube; the two tapered sides joining together to form the pentagonal truncated cone will be different than the tapered side that joins with tapered sides of other truncated cones to achieve totally flush joins in the network of joins in the Geodesic structure. Same for the equilateral tri-angular tapered tubes. Also new calculations for the number of tubes needed and the angle of taper on the sides of the tapered tri-angular tubes are needed than those given by Fishbeck.
This honeycomb skeletal enclosure formed from the hollow Pentagonal and Hexagonal pyramidal frustums of this present invention differs from previously proposed Geodesic structures such as the polyhedral structure proposed by Yacoe in U.S. Pat. No. 4,679,361 in that this skeleton is formed from a network of hollow pyramidal frustums (FIG. 3a & 3b) the thickness and length of the hollow pyramidal frustums can be chosen, such that, for a material of given tensile strength, a Geodesic honeycomb skeleton can be erected which would be the strongest structure formed, and which could be formed using this material